Board

• The lines looks too thin
• The chips should always be the same direction
• The connectors / the potentiometer should be on the panel. Not on the board.
• There is no extra pads for future modification of the TF
• Have a universal pattern for future expansion

Schematic diagram

• Increase the gain of the 1st stage for the low input noise
• What's the purpose of TP7-10? They only shows 0V when their are correctly working...
• Strange wiring at around U3
• Are +/-12V power intentional choice? Why not +/-15V?
• Why U7 is an attenuator in stead of an amplifier?

• Use 7805 in stead of using the voltage divider for the power supply.
  The current consumed by the comparator changes the divided voltage. This changes the reference level of the comparator.
  In the worst case this causes the oscillation.
• Is it a good idea to pull up the boost input with the +5V source through a reasonably high resistance?
  This will allow us to use a terminator plug (or a potentiometer) to control the boosts.
• Write the threshold voltages of the comparators on the schematic diagram for the easy understanding of the boost control.
• The comparators have no hysteresis (positive feedback). What do you do about chattering of the comparators?

• Is it OK to get the phase shift ctrl form the voltage division of the +12V supply? Don't we need a reference voltage?